Since free radicals are chemically very unstable compounds, they have a strong tendency to take electrons from other compounds around them to become stable compounds. As a result, the molecules around the free radicals easily lose their electrons and get oxidative damage, and also the molecules themselves become free radicals and attack compounds around them, which can take place continuously in a series of reactions. These free radicals are naturally produced through life activities in a human body. Typical free radicals include superoxide radical (O2—), hydroxyl radical (HO.) and hydrogen peroxide (H2O2) derived from oxygen (stable molecular state of ground state triplet oxygen) which is essential for energy production in order to maintain life, and reactive oxygen species (ROS) such as singlet oxygen (1O2) which are highly reactive free radicals.
The reactive oxygen species oxidatively damage the fat, protein, and genes that constitute a human body, thereby causing not only aging but also cancer, brain disorders such as stroke and Parkinson's disease, heart disorder, ischemia, arteriosclerosis, skin damage, inflammation, rheumatism, autoimmune disorder, and the like. A human body has antioxidation enzyme system such as superoxide dismutase (SOD), peroxidase, catalase and glutathione peroxidase as a means to protect the human body from these reactive oxygen species. Various environmental factors such as various chemical substances, food additives, smoking, drinking, ultraviolet rays, and pollution-or environmental contamination-caused mental stress destroy the balance of our body to generate an excessive amount of reactive oxygen species than needed for normal life activity of a human body. Such an excessive amount of reactive oxygen species may exceed the body's ability of self-antioxidation protection system, thereby increasing the occurrence of various disorders and speed of aging.
An antioxidation activity refers not only to an ability to prevent excessive production of reactive oxygen in vivo, but an ability to prevent oxidation that causes irreversible damage to cells. The substances which have such antioxidation activity are called antioxidants, and they are divided into synthetic antioxidants which are artificially synthesized, and natural antioxidants that exist in nature. Antioxidants are widely used in various fields such as drugs, food, cosmetics and feed. Examples of synthetic antioxidants developed so far include butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and nordihydroguaiaretic acid (NDGA), etc., and natural antioxidants include antioxidation enzymes such as superoxide dismutase, peroxidase, catalase and glutathione peroxidase, etc., and non-enzymatic antioxidants such as ascorbic acid (vitamin C), tocopherol (vitamin E) and carotenoids. However, long term use of synthetic antioxidants in a human body is restricted because they are not only easily destroyed by heating due to their heat labile property, but also have a disadvantage that their reactive oxygen-elimination effect in vivo is not sufficient and various disorders such as allergy and cancer can be induced in the human body. Therefore, attempts have been actively made to find an antioxidant substance from natural products which has high antioxidation activity but does not show harmful effect on a human body. As the natural antioxidant substances, certain plant extracts such as green tea, E. senticosus, ailanthus, chrysanthemum, persimmon leaf, Aurescens, Harlequin glorybowe, wild rosebush, wild rosebush, dandelion, safflower, timber, and the like are known to be effective, and food additives, cosmetic compositions and pharmaceutical compositions using the same have been researched and developed (Korean Patent No. 1258696 and Korean Patent No. 0682319). Despite these efforts, however, there are a myriad of unknown antioxidants in nature. Therefore, the need for research and development of a natural antioxidant substance with better antioxidation activity is increasing day by day.
It is known that Ceriporia lacerata is a kind of white-rotting fungus and conducts co-metabolism, i.e., lignin decomposition, in order to use carbon sources such as cellulose, hemi-cellulose, other polysaccharides, and glycerol, etc., in the ecosystem. However, it has not been reported that Ceriporia lacerata has excellent antioxidation activity, and the extracts thereof have not been reported to have antioxidation activity.
Accordingly, the present inventors have found that an extracellular polysaccharide produced by Ceriporia lacerata or a mycelial culture medium of Ceriporia lacerata containing the same, or dried powders or an extract thereof has an antioxidation effect and completed the present invention which is related to a composition for antioxidation comprising the extracellular polysaccharide, the mycelial culture medium, dried powders, or the extract, as an active ingredient.